Ep. 5 | Teardown of a ¥20 Pinduoduo brushless folding mini fan — surprisingly good value
Creator’s own settings as stated in the video (timestamps link to the moment). Not official values — test on scrap first.
Bill of materials
Welder, accessories, consumables and parts used in this build; quantities and specs are editable Download BOMDescription
Teardown of a ¥19.38 Pinduoduo FC-6638D folding mini fan: confirmed a 1503 brushless motor, 5-blade prop, 10 speeds on a 7-segment display, about 50 g of thrust; the cells are unlabelled, in parallel, with no BMS — swapped for two high-capacity cells plus a BMS on an AWithZ welder, now 5000mAh
A follower recommended a so-called brushless turbo mini fan, ¥19.38 paid (model FC-6638D, rated 1800mAh, 91×35×191mm, Type-C charging, folding). Features: about 10 speeds, a small 7-segment display, plenty of airflow, about 50 g of thrust at the top speed, folds for easy carrying. Inside: the main connections use plugs, easy to service; lots of motor wires, confirmed brushless, the motor should be a 1503, 5-blade prop. The cells are pretty poor: no capacity rating, no markings at all, negatives joined so they are in parallel, and the unit has no BMS. Since it is open anyway, swap in two high-capacity cells and add a BMS against over-charge and over-discharge, welded on the AWithZ welder, quite handy, straight up to 5000mAh, twice the original. Verdict: great value for ¥20, suspect the seller is running a charity — a controller board alone for a home-made 1S brushless fan costs ¥20-odd online. 1368 comments: many report later batches cut corners with only one cell, and a price rise; someone from the same shop plans to fit 2 EVE 33V cells; someone shows a fan with 800-odd grams of thrust.
Outcome
| Goal | Tear down and verify a ¥20 brushless mini fan, then upgrade the cells |
| Build | FC-6638D folding fan: 2 high-capacity cells + BMS |
| Result | Brushless confirmed; converted to 5000mAh with a BMS added · verified on camera: 94–107s opened up and confirmed brushless 1503; 146–160s mod finished |
Steps6 steps · click a frame to jump
1. Purchase and specsBrushless fan recommended by a follower, ¥19.38 paid (¥3.42 discount); FC-6638D, 1800mAh, 91×35×191mm; folding, Type-C charging.
00:03 – 00:31
2. Features: 10 speeds, 7-segment display, about 50 g thrustAbout 10 adjustable speeds, small 7-segment display, plenty of airflow; about 50 g of thrust at the top speed; folds for going out; open it up to see whether it is brushless.
00:31 – 01:12
3. Teardown: plug connections; 1503 brushless motor, 5-blade propThe main connections use plugs, easy to replace and service; lots of motor wires, confirmed brushless; the motor should be a 1503; 5-blade prop.
01:18 – 01:47
4. Poor cells and no BMS → swap cells, add a BMSThe cells have no capacity rating and no markings at all, negatives joined means parallel; the unit has no BMS, add one against over-charge and over-discharge; swap in two high-capacity cells.
01:47 – 02:17
5. Weld on the AWithZ welder, boosted to 5000mAhWelding with the AWithZ welder feels quite handy; straight up to 5000mAh, twice the original.
02:26 – 02:40
6. Verdict: great value; even a home-made controller board costs ¥20-oddThe ¥20 mini fan is great value, suspect the seller is running a charity; a controller board alone for a home-made 1S brushless fan costs ¥20-odd; that is it for this try-out and mod.
02:40 – 03:07
Bill of materials
| FC-6638D folding mini fan ×1 | Pinduoduo ¥19.38, rated 1800mAh · Teardown subject |
| High-capacity Li-ion cells ×2 | 5000mAh total · Replacement |
| 1S BMS ×1 | Over-charge / over-discharge protection |
| AWithZ spot welder (U3pro) ×1 | Welding the cells |
Measured on camera
| Thrust at top speed | 50 g 01:01 |
Creator’s tips
- Negatives joined means a parallel layout, so you can swap straight to bigger cells in parallel 01:55
- Cheap fans usually have no BMS; always add one when modding 02:09
- Plug connections make replacement and service easy 01:18
Pitfalls
- Original cells unlabelled, no BMS 01:55
- Comment: later batches cut corners with only one cell, and the price went up
Li-ion safety
- Li-ion without a BMS risks over-charge and over-discharge; add one when modding 02:09
Quotes
Cost & time
| Fan | ¥19.38 |
| Total | ¥19.38 |
Comment insightsanswered 1 · open 1 · corrections 2
Answered by the creator
Open questions
Corrections from viewers
Check other people’s videos before buying. Current brushless ones aren’t especially quiet. Anything claiming to be silent is one of these small brushed motors. Besides noise, another obvious difference is that brushless motors stop very fast, while brushed ones go limp and spin a couple more turns. Indoors, quieter is better; outdoors, brushless moves more air. The brushed motors in mini fans now are dirt cheap. The brushes wear out in one summer — my fan last year did exactly that, broke, and swapping the motor didn’t help. Even the basic red-black motors in the toy race cars we had as kids were better than this.
Reply @小火把:
Check other people’s videos before buying. Current brushless ones aren’t especially quiet. Anything claiming to be silent is one of these small brushed motors. Besides noise, another obvious difference is that brushless motors stop very fast, while brushed ones go limp and spin a couple more turns. Indoors, quieter is better; outdoors, brushless moves more air. The brushed motors in mini fans now are dirt cheap. The brushes wear out in one summer — my fan last year did exactly that, broke, and swapping the motor didn’t help. Even the basic red-black motors in the toy race cars we had as kids were better than this.
Reply @小火把:
Check other people’s videos before buying. Current brushless ones aren’t especially quiet. Anything claiming to be silent is one of these small brushed motors. Besides noise, another obvious difference is that brushless motors stop very fast, while brushed ones go limp and spin a couple more turns. Indoors, quieter is better; outdoors, brushless moves more air. The brushed motors in mini fans now are dirt cheap. The brushes wear out in one summer — my fan last year did exactly that, broke, and swapping the motor didn’t help. Even the basic red-black motors in the toy race cars we had as kids were better than this.
Reply @小火把: